53778-73-7Relevant academic research and scientific papers
Hydrogen bonding-catalysed alcoholysis of propylene oxide at room temperature
Li, Ruipeng,Liu, Zhimin,Wang, Yuepeng,Xiang, Junfeng,Xu, Yueting,Zhang, Fengtao,Zhao, Yanfei
supporting information, p. 8734 - 8737 (2021/09/08)
Alcoholysis of propylene oxide (PO) is achieved over azolate ionic liquids (IL,e.g., 1-hydroxyethyl-3-methyl imidazolium imidazolate) at room temperature, accessing glycol ethers in high yields with excellent selectivity (e.g., >99%). Mechanism investigation indicates that cooperation of hydrogen-bonding of the anion with methanol and that of the cation with PO catalyses the reaction.
Epoxide ring opening with alcohols using heterogeneous Lewis acid catalysts: Regioselectivity and mechanism
Deshpande, Nitish,Parulkar, Aamena,Joshi, Rutuja,Diep, Brian,Kulkarni, Ambarish,Brunelli, Nicholas A.
, p. 46 - 54 (2019/01/04)
Lewis acidic catalytic materials are investigated for the regioselective ring opening of epoxides with alcohols. For ring opening epichlorohydrin with methanol, the catalytic activity shows a strong dependence on the type of support and Lewis acidic species used. While Sn-SBA-15 is catalytically active, significantly higher catalytic activity can be achieved with hydrothermally synthesized zeolites of which Sn-Beta is 6 and 7 times more active than Zr-Beta or Hf-Beta, respectively. Sn-Beta is determined to be more active and more regioselective for epoxide ring opening of epichlorohydrin with methanol than Al-Beta. For Sn-Beta, the activation energy for the reaction between epichlorohydrin and methanol is determined to be 53 ± 7 kJ mol?1. For epichlorohydrin, the activation energy barrier and experimentally observed regioselectivity are found using DFT to be consistent with a concerted reaction mechanism involving activation of the epoxide on an alcohol adsorbed on the catalytic site and nucleophilic attack by a second alcohol. The epoxide is shown to impact the regioselectivity and the mechanism since isobutylene oxide is selectively ring opened by methanol to form the terminal alcohol. DFT calculations indicate the mechanism for isobutylene ring opening involves epoxide activation and ring opening on an alcohol adsorbed onto the catalytic site. Finally, catalyst reuse testing indicates that Sn-Beta can be used for multiple reactions with no decrease in activity and limited to no leaching of the tin site, demonstrating Sn-Beta is a promising catalytic material for epoxide ring opening reactions with alcohols.
Scalable and super-stable exfoliation of graphitic carbon nitride in biomass-derived γ-valerolactone: Enhanced catalytic activity for the alcoholysis and cycloaddition of epoxides with CO2
Xue, Zhimin,Liu, Feijie,Jiang, Jingyun,Wang, Jinfang,Mu, Tiancheng
, p. 5041 - 5045 (2017/11/09)
Biomass-derived γ-valerolactone (GVL) could exfoliate bulk g-C3N4 to form a super-stable dispersion of few-layer g-C3N4 nanosheets with a high concentration of up to 0.8 mg mL-1 due to the polarity and the appropriate surface energy of GVL. The exfoliation process can be easily extended to a 200 ml scale and should be extended further. The formed g-C3N4 nanosheets showed enhanced activity for the alcoholysis of epoxides and the cycloaddition of epoxides with CO2 owing to their higher specific surface areas and more exposed active centers than the bulk g-C3N4. This affords a green, facile and scalable method to form few-layer g-C3N4 nanosheets and further expand the application of g-C3N4 materials to the field of non-photocatalysis.
Graphite oxide: A simple and efficient solid acid catalyst for the ring-opening of epoxides by alcohols
Mirza-Aghayan, Maryam,Alizadeh, Mahdi,Molaee Tavana, Mahdieh,Boukherroub, Rabah
, p. 6694 - 6697 (2014/12/11)
A simple, efficient, and general procedure for the ring-opening of epoxides with various alcohols to give the corresponding β-alkoxy alcohols using graphite oxide (GO) as the catalyst, under very mild reaction conditions is described. The method proceeds in good to excellent yields and in short reaction times at room temperature under metal-free conditions.
The synthesis of butene glycol ethers with aluminium triflate
Terblans, Yvette M.,Huyser, Michelle,Young, Desmond A.,Green, Michael J.
, p. 859 - 866 (2007/10/03)
The use of aluminium triflate as a ring-opening catalyst for butene oxide (BuO) was evaluated in the presence of different alcohols such as methanol, ethanol, n-propanol, n-butanol, 2-propanol, 2-methyl-1-propanol, and 2-methyl-2-propanol. The reaction with methanol was studied kinetically by varying the temperature, catalyst concentration, and methanol - butene oxide molar ratio. These reactions yielded two major products (2-methoxy-1-butanol and 1-methoxy-2-butanol) in a approximate ratio of 1:1. It was noted that at low catalyst concentrations (5 ppm), low temperatures (90 °C), and a MeOH-BuO molar ratio of 8:1, the selectivity of the reaction could be kinetically manipulated to shift the product ratio towards 1-methoxy-2-butanol, the α-alkoxyalcohol. This result was confirmed by an experimental design program. Statistical calculations using the data from the experimental design identified a feasible region in which reactions with methanol could be carried out, which would lead to slightly higher selectivities to 1-methoxy-2-butanol. This region shows that the methanol - butene oxide ratio should be 8:1, the temperature between 80 and 85 °C, and the catalyst concentration between 3.9 and 5 ppm. These reaction conditions were used to carry out a test reaction with methanol and an extended series of alcohols. All the alcohols, except for 2-methyl-2-propanol, reacted with butene oxide under these conditions, with the selectivity to the α-alkoxyalcohol higher than to the β- alkoxyalcohol. To obtain a ring-opening reaction with 2-methyl-2-propanol, it was found that a higher catalyst concentration (approximately 10 ppm) and a lower alcohol - butene oxide ratio (6:1) at a temperature of 80 °C were necessary. This reaction led to a mixture of 1-tert-butoxy-2-butanol and 2-tert-butoxy-1-butanol with the selectivity to the α-alkoxyalcohol being somewhat higher because of the steric influence of the bulky tert-butoxy group.
Aluminium triflate as catalyst for epoxide ring-opening and esterification reactions - Mechanistic aspects
Terblans, Yvette M.,Huyser, Johannes J.,Huyser, Michelle,Green, Michael J.,Young, Desmond A.,Sibiya, Mike S.
, p. 854 - 861 (2007/10/03)
A1(CF3SO3)3 is a highly effective catalyst for the ring opening of epoxides with methanol, as well as for the esterification of carboxylic acids with alcohols. Factors that influence the rate of the ring opening of butene oxide with methanol and the esterification of acetic acid with n-propanol and ethanol were investigated. It was found that low concentrations (e.g., ～5 ppm) of Al(CF3SO3) 3 catalyze the ring-opening reactions, whereas considerably higher concentrations are required for esterification reactions. Molecular modeling studies suggest that these differences can be rationalized in terms of the formation energies of the active intermediates of these reactions.
Aluminium triflate: A remarkable Lewis acid catalyst for the ring opening of epoxides by alcohols
Bradley,Williams,Lawton, Michelle
, p. 3269 - 3272 (2007/10/03)
Al(OTf)3 was found to be an extremely effective catalyst (at ppm levels) for ring opening reactions of epoxides using a range of alcohols. The Royal Society of Chemistry 2005.
Solvomercuration-Demercuration. 8. Oxymercuration-Demercuration of Methoxy-, Hydroxy-, and Acetoxy-Substituted Alkenes
Brown, Herbert C.,Lynch, Gary J.
, p. 531 - 538 (2007/10/02)
The oxymercuration-demercuration (OM-DM) of a series of methoxy-, hydroxy-, and acetoxy-substituted alkenes was examined.The systems examined were the allyl, crotyl, 3-buten-1-yl, 4-penten-1-yl, and 5-hexen-1-yl.The methoxyalkenes undergo hydration with very high regioselectivity and almost quantitative yield in all cases.However, a small -I effect is observed in the case of the allylalkene (97.1percent Markovnikov vs. 99.5percent in 1-hexene).Moreover, in the crotyl case, a major directing effect is observed: 97.7percent 3-ol, 2.3percent 2-ol.The other three alkenes undergo the OM reaction with no effect from the methoxy group (99.5percent Markovnikov isomer).In contrast, only allyl-, crotyl-, and 3-buten-1-yl alcohols produce major amounts of hydrated products, the diols.While no hydroxyl group directing effect is observed in the allyl system, a major one is again seen in the case of the crotyl: 93.5percent l,3-diol and 6.5percent l,2-diol.The major products from the 4-penten-1-yl and 5-hexen-1-yl and alcohols are 2-methyltetrahydrofuran and 2-methyltetrahydropyran, respectively, resulting from OH-5 and OH-6 neighboring group participation in the OM stage.The acetoxy alkenes undergo hydration to give diols in ca. 80percent yield with ca. 20percent unreacted starting material.This is the result of a competitive deoxymercuration reaction which is occurring in the DM stage.However, the yield of hydrated products can be increased by varying the amount of base used in the DM.Neighboring-group participation, AcO-5, is observed in the allyl system only, resulting in a 65percent yield of the Markovnikov oxymercurial, by 1H NMR analysis, and a 35percent yield of the acetoxy-exchanged mercurial.Again, a major -I-directing effect of the acetoxy group was observed in the crotyl system but not in the others.In addition to the expected l,2- and l,3-diols, the OM-DM of crotyl acetate also resulted in small amounts of the unexpected 2,3-diol under kinetic conditions.Finally, a modified DM procedure has been developed which is compatible with the acetoxy group.
Hydroboration. 57. Hydroboration with 9-Borabicyclononane of Alkenes Containing Representative Functional Groups
Brown, Herbert C.,Chen, Jackson C.
, p. 3978 - 3988 (2007/10/02)
The hydroboration of alkenes containing representative functional groups was examined with 9-borabicyclononane (9-BBN) in order to extend the hydroboration reaction for the preparation of functionally substituted organoboranes.Terminal alkenes containing a remote functional group are hydroborated with a remarkable regioselectivity (>=98percent terminal), producing the corresponding stable organoboranes. 9-BBN hydroborates the allylic derivatives so as to place boron essentially on the terminal carbon atom (>=97percent).The directive effect is further enhanced (>=99percent) in the case of β-methylallyl derivatives.The hydroboration of crotyl derivatives attaches boron predominantly at the 2-position, followed by an elimination-rehydroboration sequence.However, crotyl alcohol can be protected against elimination as the tert-butyl or tetrahydropyranyl ethers.The hydroboration-oxidation of ethyl crotonate involves a series of elimination, hydroboration, and condensation processes.In the vinyl, crotyl, and isobutenyl systems, the mesomeric effect of the substituent favors the placement of boron at the β-position, while the inductive effect favors the α-position, with the former effect predominating in most cases.Acyclic β-substituted organoboranes undergo rapid elimination.Nonpolar solvents and lower reaction temperatures decrease the rate of elimination.However, those derived from cyclic vinyl derivatives are relatively stable under neutral conditions, undergoing facile elimination in the presence of a base.
